How to replace a string using JS?

Question

Somewhere in the html file I have the following lines :

/*my lines*/ $(function(){i=1;}); /**********/

I need to dynamically replace this lines using js with this

/*my lines*/ $(function(){i=2;}); /**********/

This is what I tried

var outerHTML = document.documentElement.outerHTML;
outerHTML = outerHTML.replace("/*my lines*/","/*my lines*/$(function(){i=2;});");

But my regex is not correct. How can I replace it ? How to locate the substring that starts with /*my lines*/ and ends with /**********/ ?

You only want i=1 replaced with i=2? Why don't you outerHTML.replace("i=1","i=2"); Also what do you mean with "But my regex is not correct"? — Thealon
– Thealon, Commented May 18, 2015 at 14:03
Because, i=1 may not be unique. I have /*my lines*/ string to make sure I am replacing the right i=1 — Pasha
– Pasha, Commented May 18, 2015 at 14:05
Also, I do not know what is inside the /*my lines*/ $(function(){i=1;}); /**********/ . It may be anything. I need to locate the string based on its beginning /*my lines*/ and ending /**********/ — Pasha
– Pasha, Commented May 18, 2015 at 14:07
Okay you could try: {/*REPLACE*/i=1;} outerHTML.replace("/*REPLACE*/i=1","/*REPLACE*/i=2"); — Thealon
– Thealon, Commented May 18, 2015 at 14:07

Radonirina Maminiaina · Accepted Answer · 2015-05-18 14:06:37Z

3

Don't use quote to declare regex. Because in your code, javascript think that you use a string instead of a regex.

outerHTML.replace(/\/\*my lines\*\//g,"/*my lines*/$(function(){i=2;});");

answered May 18, 2015 at 14:06

Radonirina Maminiaina

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Samir Das · Accepted Answer · 2015-05-18 14:06:26Z

2

Try this

console.log(str.replace(/\/\*my lines\*\/.*\/\*\*\*\*\*\*\*\*\*\*\//,"/*my lines*/$(function(){i=2;});"));

answered May 18, 2015 at 14:06

Samir Das

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Thealon · Accepted Answer · 2015-05-18 14:11:25Z

This will provide your answer:

Each HTML element has an innerHTML property that defines both the HTML code and the text that occurs between that element's opening and closing tag. By changing an element's innerHTML after some user interaction, you can make much more interactive pages.

However, using innerHTML requires some preparation if you want to be able to use it easily and reliably. First, you must give the element you wish to change an id. With that id in place you will be able to use the getElementById function, which works on all browsers.

After you have that set up you can now manipulate the text of an element. To start off, let's try changing the text inside a bold tag.

Example:

<script type="text/javascript">
function changeText(){
    document.getElementById('boldStuff').innerHTML = 'Fred Flinstone';
}
</script>
<p>Welcome to the site <b id='boldStuff'>dude</b> </p> 
<input type='button' onclick='changeText()' value='Change Text'/>

However, this is with user interaction, you could change it so that this function will be called in another function wich will trigger this.

Guffa · Accepted Answer · 2015-05-18 14:08:18Z

1

That's not a regular expression at all, that's a string. The replace method doesn't try to turn the string into a regular expression, it will just replace the first occurance of the string.

You need to escape the * characters in the regular expression, and the / characters if you use a regular expression literal:

outerHTML = outerHTML.replace(/(\/\*my lines\*\/)[^\/]+(\/\*+\/)/g,"$1 $(function(){i=2;}); $2");

answered May 18, 2015 at 14:08

Guffa

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